Apparatus and process for gas and heat recovery from digester blowoff exhaust vapors



March 16 1926. 1,576,643 v L. B. DECKER APPARATUS AND PROCESS FOR GAS AND HEAT RECOVERY FROM DIGESTER BLOW-OFF,EXHAUST VAPORS Filed June 22. 1925 11 1 4 6 6/E I 4 li W L15, Decker Inventor Y Attorney Patented Mar. 16, 1926.

UNITED STA I EMUEL B. DECKER, OF KENOGAMI, QUEBEC, CANADA.

APPARATUS AND PROCESS FOR GAS AND HEAT RECOVERY FROM DIGESTER BLOW- OFF EXHAUST VAPORS.

Application filed June 22, 1925. Serial No. 38,891.

To allwhom it may concern:

Be it known that I, LEMUEL B. DECKER, a citizen of the United States, residing. at Kenogami, Province of Quebec, Canada, have invented certain new and useful Improvements in Apparatus and Processes for Gas. and Heat Recovery .from Digester.

Blow-OE Exhaust Vaporsyand I'do hereby declare athatthe following is a full, clear,

and exact description of the'invention, such as will enable others skilled in the art to which it appertains to' make and use the same.

The present invention pertains to a novel apparatus and process for gas and heat re covery from digester blow-0E exhaust vapor Rchips, the latter are delivered. to a digesterwhere they are cooked inthe usual manner.

The vapor arisingfrom .this'cooking is led to-another batch of chips inthe manner. de-

scribed. y a

Thezinvention is fully disclosed inthe following description and in the accompanying drawings:

The installation comprises a. digester 1, and chi bin 2 arranged tocommunicate therewit as by being in: superposed relation, preferably Within a housing 3. The tops of the .digester 1 and chip bin 2 are .provided' with removable covers 4 and .5 for filling purposes as pointed out below.

The lower end of the'chi bin 2 is provided with agate or sli e 6, theoutlet thus formed being in direct alinement with the upper end of digester 1. Outlet pipes 7 and 8 extend from thelower ends of digester 1 and chip bin. 2 respectively, preferably passing through the housing 3.

Near the bottom of the housing and adj acent thereto is built a. blowpit 9 into which the outlet pipe of digester 1 extends. The outlet 8 of the chip bin 2 is connected to the blowpit by meansof a branch 10, the

pipes 8 and 10 being connected by means of a T'11. The pipes 7 and 8 are provided with valves 12 and 13 respectively.

A vacuum pump 14 is disposed at any convenient position and engages by meansof a vacuum line 15 with the upper end of chip bin 2. This linecontains a valve 16. Instead of the pump, a fan (not shown) may be placed in the line 8 between the T 11 andvalve 13. The fan would be placed to draw from pipe 10 and blow towards the chip bin. v A

An exhaust pipe 17 is fitted into the remaining branch of the T 11 and is equipped with a valve 18.

The operation of the device is as fol lows: Y 1

The digester l is filled with chips and acid in'the usual manner. The'cover 5' is now removed from the'chip'bin'2, and'this is filled also with chips. The cover 5is now replaced upon the chip-bin 2. Digester 1 is then cooked in the usual-manner.

Before blowing, the :valves16 and 13"are opened. Valve 18 is closed, the pumpi14 is started, creating a vacuumfrom thetop 8, and through the chips contained in' chip bin 2,:a'nd through: the vacuum line'15;

.-=The valve "12'beneath digesterl is now opened, whereupon the contents is dis- 'charged' into the blowpitq" The'vapor aris'- and is discharged through .the vacuum ump ofblow'pit 9, through branch 10, outer pipe 14. When the digester 1 is'finishedja low-" ing, the "pump 14"is' stopped. The cov'er l ongdigesterl is now removed, slide 6 is pulled from the bottom of chip bin 2, and the contents of'the latter dropped or conducted into the digester 1. Theusual digesting process is now carried onfin 'digester 1."- The slide 6 is"closed, valves 13-and 16 are closed, the cover 5 is removed from the top o'f chip bin 2, and the latter is filled with fresh chips in the usual manner. The process is continued in the manner described.

The exhaust 17 is used when the system is obstructed, as when under repair, or when the chip bin 2 is not .being used. In suchcases the valve 18 is opened and valve 13 is closed, and the exhaust vapor passes through pipe 17 into the atmosphere according to the usual manner of cooking.

The princi 1c of the invention as thus described ma e extended to an interrelated system of igesters and chip bins. The advantages of this rocess are as follows:

1. Uniform moisture in chips.

2. Uniform temperature of chips.

3. High increase in temperature of chips.

4. Saving in steam due to the high temperature of the chips.

5. Gas recovery.

6. Better quality of pulp.

7 A higher yield of pulp per digester.

While a specific embodiment of the invention has been illustrated and described, it is to be understood that various alterations in the details of construction may be made without departing from the spirit of the invention as indicated by the appended claims.

Havin thus fully described the invention what I cl aim as new and desire to protect by Letters Patent is cooking of wood pulp consisting in conduct- 'ing said vapor-into a quantity of wood chips prior to cooking said chips, conducting said vapor treated chips into a digester, and cooking them in said digester.

3. A process for recovering gas and heat from digester blow-off exhaust vapor in the cooking of wood pulp consisting in conducting said vapor into a quantity of wood chips prior to cooking said chips, and conducting said vapor treated chips into said digester after the latter has been blown.

4. An apparatus for recovering gas and heat from digester blow-off vapor in the cooking of Wood, comprising a digester having an exhaust and an inlet, a chip bin adapted to communicate with the digester inlet, and means for conducting vapor from the digester exhaust to said bin.

5. An apparatus'forrecovering gas and heat from digester blow-off vapor in the cooking of wood, comprising a digester having an exhaust and 'an inlet, a blowpit in" communication with said exhaust, a chip bin adapted to communicate with the digester inlet, and means for conducting vapor from said pit to said bin.

6.'An apparatus for recovering gas and heat from digester blow-off vapor in the cooking of wood, comprising a digester having an exhaust and an inlet, a blowpit in communication with said exhaust, a chip bin adapted to communicate with the digester inlet, a pipe connecting said pit to said bin, and means for drawing vapor through said pipe from the pit to the bin.

In witness whereof I have hereunto set my hand.

LEMUEL B. DECKER. 

